Recently, information recording-reproduction apparatuses utilizing optical techniques have been widely studied and developed. For example, in magneto-optical recording-reproduction apparatuses, thermomagnetic recording making use of the phenomenon that magnetic characteristics of a magneto-optical recording medium vary with temperatures is adopted for writing information, while the Faraday effect and the magnetic Kerr effect are utilized for reproducing information.
On the other hand, in a technical research report of Electronic Information Communication Institute, Magnetic Recording Seminar (MR) 79-3, P. 21(1979), there is described an information recording-reproduction apparatus wherein analog signals are recorded on a magnetic tape through thermomagnetic recording, and reproduced by a magnetic head. Chromium dioxide is used as a material for the magnetic layer of the magnetic tape. During recording, while converging a light beam with a predetermined intensity on the magnetic layer of the travelling magnetic tape to cause a required temperature change on an extremely limited area on the magnetic layer, a residual magnetization is formed on the magnetic layer in response to a magnetic field applied from a recording-use magnetic head by supplying the recording-use magnetic head with a driving current varying with analog signals. The information thus recorded is reproduced by a reproduction-use magnetic head.
In the above arrangement, as long as the condition that a width of the reproduction-use magnetic head is smaller than the pitch of recording tracks on the magnetic tape is satisfied, a high S/N can be achieved during reproduction, since crosstalk from adjoining tracks can be minimized.
However, if the density of the recording tracks is increased in order to increase the recording capacity, the pitch of the recording tracks should be made narrower, thereby arising a problem that it is difficult to manufacture reproduction-use magnetic heads satisfying the above condition.